I don't think you're using the same definition of "opportunity" as the FAA.
From what I'm hearing/reading, the FAAs definition of "opportunity" goes
more toward the cirmcumstances from which the flight arose. If you are
going flying and you invite me to come along for a ride from Buffalo to
Flushing, NY...no problem. But, if I say to you, I've been meaning to go to
Flushing, NY. Hey, I know, why don't you fly me up there? .. and you agree
(and even if YOU pay all the costs involved...) then this is a violation of
the idea of commonality. My needing to go to Flushing is providing you with
an opportunity to log time because of me...not because you suggested it.

"The idea of commonality" is something the FAA made up out of whole
cloth, bypassing the normal rulemaking procedure.

The "opportunity" to fly to Flushing was not provided by you. Icould
still go to Flushing if I wanted to, irrespective of your request.
Instead, what was provided was the opportunity to have my flight
=benefit= you.

You're splitting hairs...
The FAA splits hairs. In fact they split short hairs.
No argument here...but I hope the FAA never gets near my short hairs.

Then it would behoove you to split long hairs.

But if you go fly with the primary reason being the
taking of your sister to visit her friend, (as a private pilot) IMO, you
would be doing so in potential violation of the way in which the FAA has
interpreted this situation in the past.

This seems to be true. It is also asinine. (and my rants, if they be
interpreted as such, are directed at the part of the FAA that comes up
with and defends this kind of thing, not at you or any other poster)

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.